Dental grinding device and process



19 1927. J. w. NEEDLES DENTAL GRINDING DEVICE AND PROCESS Filed March15' 1926 2 Sheets-Sheet 1 fly \L /6 9 Z8 I I 3/ .2

"1 INVENTOR.

ATTORNEIQ J ly 19.1927, I 1,636,321

J. w. NEEDLES DENTAL GRINDING DEVICE AND PROCESS Filed March 15,1926 2Sheets-Shae! 2 f v l pZ 7 2/ 49 47 Eye/Ila;

E I I Patented July 19, 1927.

UNITED STATES PATENT OFFICE.

JOHN W. NEEDLES, OF KANSAS CITY, MISSOURI, ASSIGN'OR OF oNE HALF TOMILUS M.

' HOUSE, 01: KANSAS CITY, MISSOURI.

, DENTAL GRINDING DEVICE AND rnocnss.

Application filed mm 15, 1926. Serial No. 94,763.

The present invention relates to dental appliances, and aims to providea novel and eflicient form of occlusal grinding device for use witharticulating apparatus, such as is employed in the making of artificialdentures or like work. The principal object in view is to provide amechanism which may be applied to articulators for the purpose ofperforming such a grinding operation as will eliminate the lockedrelation which commonly exists between sets of artificial teeth.especially in central occlusion, my improved grinding operationresulting in a horizontal freedom of movement of the dentures in thevarious positions of occlusion which they may assume.

For the purpose of performing this function, I have devised a grindingprocess, which consists in combining with the usual grinding movementswhich characterize the common forms of articulators, a further componentof grinding movement of such a character that the resultant movementwill produce a grinding effect simulating that due to the ordinarywearvof natural teeth in their normal use, whereby the locked relationof the cusps is eliminated, since the necessary clearance is providedbetween them for permitting a proper horizontal freedom of movementin-all positions of occlusion. More specifically, the process is carriedout by producing relative movement of the dentures in both directionslaterally, as in the usual practice, but at the same time a furthercomponent of movement, preferably rectilinear and angularly withreference to said lateral movement, is continuously imparted to one ofthe dentures in the same horizontal plane. 7 7

As carried out in practice, I have devised a grinding device adapted tobe removably applied to the artic ulator, and including a movable platehaving means of attachment to the upper denture and provided with anactuating element adapted to effect the de sired form of linear movementof said movable plate in the grinding operation. A suitable drive isprovided for actuating said ele ment, the arrangement of which issuchthat one of the components of the relative movement of the denturesw ll correspond to a relative retrusive movement of the lower denture,starting with both dentures in nor mal central occlusion.

It is further sought to provide a device of the character described inwhich provision is made for initially adjusting the position of themovable plate sothat it will'be symmetrically arranged with reference towhat is known as the sagittal plane.

With the foregoing principal objects in view, as Well as various minorobjects which will appear in the course ofthe detailed description, theinvention will now be described by reference to the accompanyingdrawings illustrating one form of construction which I have devised forembodying the proposed improved mechanism, after which those featuresand combinations deemed to be novel will be particularly set forth andclaimed.

In the drawings 1 Figure 1 is a side elevation, illustrating anarticulator having an occlusal grinding device constructed in accordancewith the pres ent invention;

Figure 2 is a plan view of the same;

Figure 3 is a central vertical section, taken on the line IIIII I ofFigure 2, the denture models being omitted; V

Figure 4 is a horizontal section. taken on the'line IVIY of Figure 1;and

Figure 5 is a detail section, taken on the line V-V of Figure 2.

Referring now to the drawings in detail, these illustrate the improvedocclusal grinder in its operative relation to a cornmon and well knownform of articulator now in commercial use, this articulator conipris inga lower supporting frame 7 and an upper frame member 8 which is movablysup ported upon the lower frame 7 for pivotal sliding movement by meansof what are known asrotation points 9, 10, engaging suitably curved orinclined surfaces, as required for accommodating the movement of theupper frame member 8 in accordance with the different occlusal positionsassumed by the upper denture 11 with reference to the lower denture 12(see Figure l). The

ill)

middle portion of the upper frame member s To'the lower frame member 7,is detachably secured, as by means of the clamping the upper frame 8,said upper model sup port, however, not being illustrated in thedrawings, but being displaced by the grinding device forming the subjectof the pres entapplication.

The improved grinding device herein illustrated is designed to bemounted in lieu of the upper denture model support in any of the commonforms of articulators, the connection in the present construction to theupper articulator frame 8 being made by means of the attaching screws 21already present for the attachment of the upper model supporting arm,these screws 21 onerating to secure the rear end of the fixed grinderplate 22, the forward end of which is provided with a passage for theupper end of the incisor pin 18, which is held in position by means of aclamping screw 24.

To the under face of the'plate 22 is applied the movablegrinder plate 25which is provided with retaining screws 26 for'holding the plaster cast,27 that supports the upper denture model 11. The plate 25 is supported.by means of a set of screws 28, the lower ends of which are suppliedwith nuts 29 engaging the under face of the plate 25; openings 30 areprovided in the plate 22 of sufiicient size to acconunodatetheimovements of the screws 28 correspondingto the movement er the plate25, the heads ofsaid screws being engaged by washers '31 supported bythe margins of the openings 30, as clearly shown in'Figure 2.

Secured centrally to the plate 25 is a vertical .stub shaft 32 forjournaling a belt pulley 34 on the lower hub portion'of which is formedan eccentric element 36, to which sliding movement thereof in responseto the operation of the eccentric while confining said'movement to alongitudinal or "forward and rearward ,movement,.as will be obvious. Itwill .be understood Ithat a .suitablebelt drive (not shown) is designedtobe applied to the pulley 3tfor actuating theieccentric element therebycorrespondingly actuating the plate 25.

Adjacent to the front margin of the plate 25', the same is provided withthe screw projecting upward through an opening 46 of a size sufficientto receive the lock nut 47 mounted on the screw. 45, when said nut isturned down upon said screw 45. The function of the nut 47 is, by beingclamped down within the opening 46, to initially position the plate 25in its most rearward position which it may occupy relative to plate 22,or in what is referred to in practice as p'late25 at the most rearwardlimit of its movement as above explained, the nut l? being lowered uponthe screw 45 into the opening 4'6 for this purpose; this adjustmentplaces the eccentric element 36 in forward position, that is, in frontof the shaft 32, as represented in Figure 4. This for the purpose ofinsuring that, as the grinding movement begins, with the dentures incentral occlusion, the'beginning of the movement of the plate 25 will bein a forward direction, corresponding to a relative retrusive movementof the lower denture.

After the mounting of both models in position, the nut 47 is raised intoclamping engagement with the head of the screw 45, and poweris appliedby means of the belt attached to the pulley The grinding operation iscarried out first for the position of central occlusion, the operationof the eccentric element 86 resulting in a limited rectilinear movement,longitudinally forward and backward, as guided by the keys 42, theinitial part of which movement is in a forward direction for thepurpose'of effecting a relative retrusive movement of the lower denture.

After grinding for the position for central occlusion, the articulatoris adjusted to position the teeth for what is known as tend to endbiting relation, and the operation ofgrinding is carried out for thisposition, moving the articulator from time to time until centralocclusion is reached. After this, the grinding process is carried outfor right and left lateral occlusion, each time proceeding back to theposition of central occlusion"; and following this the same prociscarried out for both positions of right and 'left lateral occlusion fromprotrusi've occlusion, and baclrto the position of central occlusion.

As in all these different grinding positions, the action of theeccentric produces a component of linear movement in the same plate butin a different direction from the lateral incisor guide movements, whichare effected by hand as usual, the resultant movement produces acomplete grinding action of the contacting cusp facets of the dentures(both front and rear faces), thus giving a perfect freedom from thelocked conditions not possible with ordinary articulator grinding.

From the foregoing it will be seen that I have provided a practical andefficient device and process for carrying out all of the desired objectsof the invention, and while I have illustrated what I now regard as thepreferred mode of practicing the invention, I desire to reserve theright to make all such changes and modifications as may fairly fallwithin the scope of the appended claims.

What I claim is:

l. A dental grinding process which consists in holding a pair ofartificial dentures in occluded relation, and producing relativemovement of said dentures substantially horizontally in both lateraldirections from central occlusion, while simultaneously imparting to oneof said dentures a longitudinal rectilinear movement and positivelyguiding saidmovement both forwardly and rearwardly.

2. An occlusal grinding device comprising the combination of means forholding a pair of dentures in occluded relation while permittingrelative movement thereof in either lateral direction, and means forimparting to one of said dentures, simultaneously with said lateralmovement, a rectilinear movement of small amplitude and positivelyguiding said movement in a longitudinal direction.

3. An occlusal grinding device for articulators comprising a plateprovided with means for detachably connecting the plate to the frame ofthe articulator, a movable denture supporting plate carried by saidfirst plate, and means for imparting to said m0vable plate areciprocatory movement of small amplitude and means for positivelyconfining said movement to a fixed rectilinear path.

4. An occlusal grinding device for articulators comprising a plateprovided with means for detachably connecting the plate to the frame ofthe articulator, a movable denture supporting plate carried by saidfirst plate, mechanical means for initially setting said movable plateat the most rearward limit of its movement, and means for imparting tosaid movable plate a reciprocatory movement of small amplitude.

5. An occlusal grinding device for articulators comprising a plateprovided with' means for detachably connecting the plate to the frame ofthe articulator, a movable denture supporting plate carried by saidfirst plate, and means comprising an eccentric element connected withsaid movable plate and coacting with said first plate for imparting tosaid movable plate a reciprocatory movement of small amplitude.

6. An occlusal grinding device for articulators, comprising a plateadapted to be secured to the articulator frame, a movable denturesupporting plate carried by said first plate, eccentric means forimparting to said movable plate a slight reciprocatory movement', andguide means mounted in and connecting said plates for positivelyconfining said movement to a fixed path.

In witness whereof I hereunto aflix my signature.

JOHN W. NEEDLES,

